Vignette problem

Eric Pascarelli · January 5th, 2008, 03:54 PM

One of the important adjustments in a film camera is centering the lens within the film gate - lenses need to be recentered when changing from academy to super 35 shooting for example, as the whole image is shifted to the side .05"

A quick way to test for whether a lens is centered is to put a target on the wall (a piece of tape will do), put zoom lens on the camera and zoom in and out. The target should remain centered on the crosshairs throughout the zoom range.

I tried this on my (as yet) unrepaired vignetting EX1 and found that the zoom does not "track" while zooming. A centered target at full tele shifts down and slightly to the right when zoomed full wide.

Question to all - vignetting and non vignetting camera owners. Does your zoom track? Be sure to test this with OIS off. Use the center marker on LCD for greater precision.

I think this will give a clue as to whether your lens is adjusted properly and whether your camera will vignette.

Thanks.

Steven Thomas · January 5th, 2008, 04:10 PM

Quote:

Originally Posted by Eric Pascarelli

Question to all - vignetting and non vignetting camera owners. Does your zoom track? Be sure to test this with OIS off. Use the center marker on LCD for greater precision.

I think this will give a clue as to whether your lens is adjusted properly and whether your camera will vignette.

Thanks.

Hmm.
I have not thought of this, I will try the test.
Also, I can only HOPE that Sony is using the SDI out when checking for this problem. This will offer them the full raster. I can't imagine they are not.
If they are relying on the LCD, you can not use this, it's to small to see the problem.

I sure got the impression they only used the LCD when I saw they turned OFF all display items for the LCD...

Paul Kellett · January 6th, 2008, 09:04 AM

I just performed the vignetting test,seems mine is ok,i also performed the zoom and track test,that was also ok so maybe these two faults are linked.Has anyone else with known vignetting tried the zoom and track test ?
I was told by my retailer that my cam was from the 2nd batch.

Eric Pascarelli · January 6th, 2008, 09:16 AM

I am sure that they are related - my lens is clearly not centered on the chip and I have the vignetting problem.

Also, there is a significant vertical error in the zoom test, and only a slight horizontal error. This is consistent with the vignetting that shows only at the top corners of the frame, and almost equally on both sides of the top.

When I zoom from tele to wide, the target (on the wall) drifts down and to the right. My vignette corners encroach on the image as if the offending circular blockage were offset in that same direction. Sounds like a predictable relationship, perhaps?

Steven Thomas · January 7th, 2008, 10:00 AM

Anyone else still having the vignetting issue?

I'm still showing the problem after the adjustment.

http://dvinfo.net/conf/showpost.php?...&postcount=434

Sebastien Thomas · January 7th, 2008, 11:08 AM

I haven't seen the problem on mine so far. I should have the 11th camera from France.

I got a hand on another one in france, and zooming to a white wall showed slight darkening on every 4 edges. Mine doesn't.

Graeme Fullick · January 7th, 2008, 03:18 PM

Steven,

My replacement cam is fine. I opted to have Sony Australia do the adjustment even though it was a replacement camera. I think that our local service engineers are very frustrated that the factory has let so many through QC. I know that my request for adjustment was justified as the service engineers said that the replacement camera sent to me did have a slight problem - but it is perfect now.

Looking at your adjusted camera - the vignetting seems apparent on all 4 corners and about to the same degree - which I have not seen before. Generally it is prominent in 2 only, or 3 in bad cases. Equal vignetting in all 4 corners would tend to indicate either a faulty lens or an incorrect forward/backward alignment (I don't even know if this is adjustable).

Time to get back to Sony your dealer with strong complaints.

Steven Thomas · January 7th, 2008, 08:13 PM

I have brought this up with Sony. I'm waiting to hear back.

Andrew Wilson · January 17th, 2008, 08:24 AM

So I just got my camera from AbelCine on a fresh shipment and it seems to be exhibiting a bit of the vignetting problem.

Is there an 'acceptable' level of vignetting?

Is there such a thing as being way out of safe area with HD?

Have others here who have had this problem seen it completely go away with service and how long was the camera out of your hands?

Thanks!

Graeme Fullick · January 17th, 2008, 03:46 PM

Andrew,

There is no level of acceptable lens misalignment vignetting. If you are seeing the black shadows in corners at 10mm and F1.9 when following the instructions on this thread - then you have it, and should return your camera for either service or replacement. Experience is that it takes only a few days to repair, and with the exception of Steven's camera all seem to have been fixed completely.

On the other hand all lenses have a degree of vignetting as they approach their long end - and the EX1's is no exception (even if it is a really good piece of glass). There will be a slight darkening of the picture starting from the corners, but moving toward the centre as you zoom in - but this should be very slight and not really noticeable except if you are really looking carefully and focussing on a perfect white wall.

Andrew Wilson · January 17th, 2008, 04:48 PM

Looks like I might be in the clear. Last night when I did the test, I was going handheld in a somewhat dark studio shooting at an unevenly lit wall.

Today I did the test shooting at an overcast sky on a tripod and didn't see any but my focus wasn't set to infinity. I did the test again with focus set to infinity but by then it was much darker and a lot harder to tell.

Steven Thomas · January 17th, 2008, 05:04 PM

Andrew,
It sounds like yours might be OK.

for a quick test, aim at a white wall, or ceiling.
Intentionally under expose.
f1.9 aperture
Slowly step through focal range 8-25mm.
I believe focus near infinity will enhance the vignette more (if any).
OIS off

Krikor Djevahirdjian · January 17th, 2008, 06:11 PM

Steven, just wondering if you resolved this issue with Sony.

Steven Thomas · January 17th, 2008, 06:23 PM

Working on it. It should be resolved by next week.

Andrew Wilson · January 17th, 2008, 08:13 PM

I assume that when you say intentionally underexpose AND set your iris to f1.9 you would compensate (if necessary) with ND filters. Right?

January 5th, 2008, 03:54 PM	#436
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	Zoom Does Not Track in My Vignetting Camera One of the important adjustments in a film camera is centering the lens within the film gate - lenses need to be recentered when changing from academy to super 35 shooting for example, as the whole image is shifted to the side .05" A quick way to test for whether a lens is centered is to put a target on the wall (a piece of tape will do), put zoom lens on the camera and zoom in and out. The target should remain centered on the crosshairs throughout the zoom range. I tried this on my (as yet) unrepaired vignetting EX1 and found that the zoom does not "track" while zooming. A centered target at full tele shifts down and slightly to the right when zoomed full wide. Question to all - vignetting and non vignetting camera owners. Does your zoom track? Be sure to test this with OIS off. Use the center marker on LCD for greater precision. I think this will give a clue as to whether your lens is adjusted properly and whether your camera will vignette. Thanks.

January 6th, 2008, 09:04 AM	#438
Paul Kellett Trustee Join Date: Nov 2007 Location: Bristol UK Posts: 1,273	Just did vignetting test and zoom/track test I just performed the vignetting test,seems mine is ok,i also performed the zoom and track test,that was also ok so maybe these two faults are linked.Has anyone else with known vignetting tried the zoom and track test ? I was told by my retailer that my cam was from the 2nd batch.

January 7th, 2008, 03:18 PM	#442
Graeme Fullick Major Player Join Date: Mar 2005 Location: Newcastle, Australia Posts: 337	Steven, My replacement cam is fine. I opted to have Sony Australia do the adjustment even though it was a replacement camera. I think that our local service engineers are very frustrated that the factory has let so many through QC. I know that my request for adjustment was justified as the service engineers said that the replacement camera sent to me did have a slight problem - but it is perfect now. Looking at your adjusted camera - the vignetting seems apparent on all 4 corners and about to the same degree - which I have not seen before. Generally it is prominent in 2 only, or 3 in bad cases. Equal vignetting in all 4 corners would tend to indicate either a faulty lens or an incorrect forward/backward alignment (I don't even know if this is adjustable). Time to get back to Sony your dealer with strong complaints. __________________ Graeme

January 17th, 2008, 03:46 PM	#445
Graeme Fullick Major Player Join Date: Mar 2005 Location: Newcastle, Australia Posts: 337	Andrew, There is no level of acceptable lens misalignment vignetting. If you are seeing the black shadows in corners at 10mm and F1.9 when following the instructions on this thread - then you have it, and should return your camera for either service or replacement. Experience is that it takes only a few days to repair, and with the exception of Steven's camera all seem to have been fixed completely. On the other hand all lenses have a degree of vignetting as they approach their long end - and the EX1's is no exception (even if it is a really good piece of glass). There will be a slight darkening of the picture starting from the corners, but moving toward the centre as you zoom in - but this should be very slight and not really noticeable except if you are really looking carefully and focussing on a perfect white wall. __________________ Graeme

January 6th, 2008, 09:16 AM	#439
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	I am sure that they are related - my lens is clearly not centered on the chip and I have the vignetting problem. Also, there is a significant vertical error in the zoom test, and only a slight horizontal error. This is consistent with the vignetting that shows only at the top corners of the frame, and almost equally on both sides of the top. When I zoom from tele to wide, the target (on the wall) drifts down and to the right. My vignette corners encroach on the image as if the offending circular blockage were offset in that same direction. Sounds like a predictable relationship, perhaps?

January 7th, 2008, 10:00 AM	#440
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Anyone else still having the vignetting issue? I'm still showing the problem after the adjustment. http://dvinfo.net/conf/showpost.php?...&postcount=434

January 7th, 2008, 11:08 AM	#441
Sebastien Thomas Major Player Join Date: Nov 2007 Location: Paris, France Posts: 210	I haven't seen the problem on mine so far. I should have the 11th camera from France. I got a hand on another one in france, and zooming to a white wall showed slight darkening on every 4 edges. Mine doesn't.

January 7th, 2008, 08:13 PM	#443
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	I have brought this up with Sony. I'm waiting to hear back.

January 17th, 2008, 08:24 AM	#444
Andrew Wilson Tourist Join Date: Nov 2007 Location: Vermont, USA Posts: 123	So I just got my camera from AbelCine on a fresh shipment and it seems to be exhibiting a bit of the vignetting problem. Is there an 'acceptable' level of vignetting? Is there such a thing as being way out of safe area with HD? Have others here who have had this problem seen it completely go away with service and how long was the camera out of your hands? Thanks!

January 17th, 2008, 04:48 PM	#446
Andrew Wilson Tourist Join Date: Nov 2007 Location: Vermont, USA Posts: 123	Looks like I might be in the clear. Last night when I did the test, I was going handheld in a somewhat dark studio shooting at an unevenly lit wall. Today I did the test shooting at an overcast sky on a tripod and didn't see any but my focus wasn't set to infinity. I did the test again with focus set to infinity but by then it was much darker and a lot harder to tell.

January 17th, 2008, 05:04 PM	#447
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Andrew, It sounds like yours might be OK. for a quick test, aim at a white wall, or ceiling. Intentionally under expose. f1.9 aperture Slowly step through focal range 8-25mm. I believe focus near infinity will enhance the vignette more (if any). OIS off

January 17th, 2008, 06:11 PM	#448
Krikor Djevahirdjian New Boot Join Date: Dec 2006 Location: New York NY Posts: 11	Steven, just wondering if you resolved this issue with Sony.

January 17th, 2008, 06:23 PM	#449
Steven Thomas Trustee Join Date: Sep 2005 Location: Gilbert, AZ Posts: 1,896	Working on it. It should be resolved by next week.

January 17th, 2008, 08:13 PM	#450
Andrew Wilson Tourist Join Date: Nov 2007 Location: Vermont, USA Posts: 123	I assume that when you say intentionally underexpose AND set your iris to f1.9 you would compensate (if necessary) with ND filters. Right?